This video, the first in a twopart training series on lassa fever, provides an overview, describing the epidemiology and clinical presentation of the virus. Lasv was first isolated in 1969 from a missionary nurse who worked in a clinic in a small town, lassa, in northeastern nigeria. Dec 30, 2016 q fever, or query fever, is a zoonotic disease caused by the bacterium coxiella burnetii. Clinical and epidemiological characteristics of yellow fever. Firsthand clinical observations of hemorrhagic manifestations in ebola hemorrhagic fever in zaire.
From 1985 to 1999, consecutive cases of q fever, presented. Nov 08, 2017 efsa assisted four countries in the analysis of epidemiological data on african swine fever asf, collected until september 2017. Mccormick jb, webb pa, krebs jw, johnson km, smith e 1987 b a prospective study of the epidemiology and ecology of lassa fever. Cattle, sheep and goats are the primary domestic animal reservoirs, and the bacteria are excreted in high numbers in birth products, milk, urine and faeces.
Clinical presentation is varied, mainly presenting with fever, malaise, abdominal discomfort, and nonspecific symptoms often confused with other causes of febrile syndrome. Lassa fever accounts for an estimated 200,000 to 500,000 cases and 5000 deaths yearly in west africa, particularly in sierra leone, nigeria, liberia and r epublic of guinea. Less commonly there may be bleeding from the mouth or. The natural reservoir of the lassa virus is multimammate rat species known as mastomys natalencesis fisherhoch et al, 1995. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Epidemiology of dengue fever in ethiopian somali region. An arenavirus was isolated from two of these patients and given the name of lassa virus after the town of lassa, nigeria, where the disease, known as lassa fever, occurred buckley et al. Dec 02, 2016 dengue fever df is globally emerging mosquito born viral disease. For 2016, eueea countries reported three cases of lassa fever. Lassa fever lf is endemic to nigeria, where the disease causes substantial rates of illness and death.
Epidemiological analyses of african swine fever in the. Lassa fever epidemiology in nigeria implications for research pdf. Epidemiological analyses of african swine fever in the baltic. Epidemiologic and environmental risk factors of rift. Lassa fever is spread through direct contact with the. We report the epidemiology of lassa fever in bauchi state, a diseaseendemic region, in nigeria.
Classical swine fever european livestock association. Therefore understanding the epidemiology of causes of fever has important implications for management of febrile patients. Epidemiologyoccurs worldwide though less commonly in the tropics1. Lassa fever is one of the hemorrhagic fevers and may appear with signs and symptoms like ebola or marburg hemorrhagic fever viruses, and until these viruses are ruled out, suspected cases must be managed with infection control precautions to prevent contact with blood, body fluids, and contaminated surfaces. Arboviral disease, atmospheric dispersal modeling, bovine ephemeral fever, conditional autoregressive model, culicoides biting midges, epidemiology, japan, mosquito, spatial analysis, windborne spread background bovine ephemeral fever bef is an arboviral short for arthropodborne viral disease of cattle and water. Efsa assisted four countries in the analysis of epidemiological data on african swine fever asf, collected until september 2017. Researching awareness, risk factors and seroprevalence of. World health organization, 2000 that is, not published by merlin, as was stated.
Ongoing research confirms that abortion waves on dairy goat farms are the primary source of infection for humans, primarily affecting people living close under 5 km. Showalter in this work, we construct and analyze a nonlinear reactiondiffusion epidemiology model consisting of two integral. Yellow fever yf, an endemic mosquitoborne viral infection of humans and nonhuman primates in tropical regions of africa and south america, is currently an important cause of haemorrhagic feverrelated death worldwide, affecting as many as 200 000 persons annually in these regions monath, 2001. The nurse presumably acquired infection from an obstetrical patient residing in lassa. Lassa fever lf, an acute viral haemorrhagic fever, is an endemic zoonotic viral infection in west africa countries with up to % case fatality rate. The fever which has afflicted over 284 has killed about 154 nigerians from different parts of. The epidemiology and clinical presentation of lassa fever.
Epidemiological analyses on african swine fever in the. Nigeria may be battling the worst outbreak of lassa fever in history. An integrated approach to the syndrome of fever in resourcelimited areas is needed to improve patient outcomes and to rationally target disease control efforts. Epidemiological notes in connection with the 1954 outbreak. Lassa fever, a new virus disease of man from west africa. Prevent, detect, and control diseases of public health importance. Lassa fever is one of the hemorrhagic fever viruses like ebola virus, marburg virus, and others unlike ebola virus, lassa fever is not as contagious person to person, nor as deadly lassa virus is typically transmitted by the urine or feces of mastomys rats to humans. African swine fever virus asfv has been notified in the baltic countries and the eastern part of poland from the beginning of 2014 up to now. Crump ja, morrissey ab, nicholson wl, massung rf, stoddard ra, et al. The epidemiology of febrile illness in subsaharan africa. Epidemiologic and clinical features of lassa fever. Epidemiologic investigations into outbreaks of rift valley. The causative agent, yellow fever virus yfv, is the prototype of the genus flavivirus family flaviviridae. It is a disease of poor environmental sanitation and hence occurs in parts of the world where water supply is unsafe and sanitation is substandard.
Pathophysiology and treatment of lassa fever springerlink. Less commonly there may be bleeding from the mouth or gastrointestinal tract. Chikungunya virus chikv is the aetiological agent of the mosquitoborne disease chikungunya fever, a debilitating arthritic disease that, during the past 7. Two hundred and eight patients 90% presented as fid, with n3 or without n75 hepatitis. Sep 11, 2016 nigeria may be battling the worst outbreak of lassa fever in history. Dengue is the most important arthropodborne viral disease of public health significance. To summarize recent studies of fever aetiology in subsaharan africa focusing on causes other than malaria. Mar 23, 2017 african swine fever virus asfv has been notified in the baltic countries and the eastern part of poland from the beginning of 2014 up to now. The disease originated in africa and then spread to south america in the 1600s. Clinical and epidemiological characteristics of yellow. Today, yellow fever is found in south america and africa. Name at least two countries where lassa fever is endemic.
Q fever annual epidemiological report 2016 2014 data. Viral hemorrhagic fevers vhfs are a group of febrile illnesses caused by rna viruses from several viral families. These highly infectious viruses lead to a potentially lethal disease syndrome characterized by fever, malaise, vomiting, mucosal and gastrointestinal gi. Lassa fever is an acute viral zoonotic illness caused by lassa virus, an arenavirus known to be responsible for a severe haemorrhagic fever characterised by fever, muscle aches, sore throat, nausea, vomiting and, chest and abdominal pain. Epidemiological notes in connection with the 1954 outbreak of. Epidemiology and control of lassa fever springerlink. Incidence peaked in late summer to early autumn each year, which coincided with incidence rate. Rift valley fever rvf outbreaks have been associated with periods of. Compared with nine reporting countries in the 1950s, today the geographic distribution includes more than 100 countries worldwide. Epidemiological analyses on african swine fever in the baltic countries and poland european food safety authority efsa, jose corti nas abrahantes, andrey gogin, jane richardson and andrea gervelmeyer abstract african swine fever virus asfv has been noti.
Scarlet fever causal agentgroup a betahaemolytic streptococci. During sporadic rvf outbreaks in 20082009 and widespread epidemics in 20102011, 302 laboratoryconfirmed human infections, including 25 deaths casefatality rate, 8% were identified. Chikungunya fever, an arboviral disease that is caused. A research manual for south africa maintains the focus on epidemiology as a discipline and incorporates the changes in policy as well as new findings and research methodologies. The objective of this study was to determine the epidemiology, clinical features and prognosis of acute q fever in our area. Epidemiology of lassa fever and factors associated with. Clinical polymorphism is a main feature of q fever and, depending upon the geographic location, differences in its clinical picture have been described. Common clinical featuressymptoms include sore throat, fever, vomiting, headache, malaise and rash on neck and chest classically a fine punctate erythema1.
These highly infectious viruses lead to a potentially lethal disease syndrome characterized by fever, malaise, vomiting, mucosal and gastrointestinal gi bleeding, edema, and hypotension. Lassa fever, viral haemorrhagic fever, mastomys introduction lassa fever lf is an acute viral haemorrhagic illness that is caused by an arenavirus. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. In this article, we report an analysis of the epidemiologic and clinical aspects of the lf outbreak that occurred in nigeria during january 1may 6, 2018.
Epidemiological trends of lassa fever outbreaks and insights for future control in nigeria article pdf available january 2017 with 2,184 reads how we measure reads. Etiology of severe nonmalaria febrile illness in northern. Mccormick jb, webb pa, krebbs jw, johnson km, smith es 1987b lassa fever. Barnett maxwell finland laboratory for infectious diseases, boston medical center, boston, massachusetts yellow fever continues to occur in regions of africa and south america, despite the availability of effective vaccines. The world health organization estimates that more than 2. Classical swine fever control epidemiology europe sus scrofa wild boar. The temporal analysis demonstrated that the average proportions of pcr and antibodyelisa positive samples from the hunted wild boar remained below 3. Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with lassa fever.
Researching awareness, risk factors and seroprevalence of lassa fever in nigeria. Yellow fever is a viral hemorrhagic fever with high mortality that is transmitted by mosquitoes. Yellow fever as an endemicepidemic disease and priorities for. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region. She died approximately one week after the onset of symptoms. Epidemiological analysis of bovine ephemeral fever in 2012. The fever which has afflicted over 284 has killed about 154 nigerians from different parts of the country from august 2015 to. The disease occurs now only in africa and central and south america, although historically, large outbreaks occurred in europe and north america. Evaluation of the impact of malaria interventions on. The history of recognized human arenavirus infection in africa began in 1969 with the mysterious death of two medical missionaries and the nearfatal illness of a third frame et al. Aetiology epidemiology diagnosis prevention and control references. The disease affects domestic and wild pigs and can involve tick vectors.
Regional epidemiological patterns involve different hosts and mechanisms of transmission. Clinical presentation of lassa fever cases during the hospital epidemic at zorzor, liberia, marchapril 1972. The lassa virus is transmitted to humans mainly through handling rats, food or household items contaminated by rats urine and faeces. Highlights african swine fever is a highly contagious swine disease with severe socioeconomic consequences. Since november 2015, at least 10 states in nigeria have been affected by an outbreak of lassa fever, an acute viral disease that causes fever, muscle pain, hemorrhage and sometimes death. Fever is among the most common symptoms of people living in africa, and clinicians are challenged by the similar clinical features of a wide spectrum of potential aetiologies. In edo state, nigeria, health researchers are collecting data on lassa fever to improve health education and protect people from getting infected.
Epidemiologic and environmental risk factors of rift valley fever in southern africa from 2008 to 2011 margaret m. The virus exhibits persistent, asymptomatic infection with. Variation in genetic diversity helped understanding asf regional epidemiological patterns. Rift valley fever rvf is an emerging zoonosis posing a public health threat to humans in africa. Dengue fever df is globally emerging mosquito born viral disease. Ongoing research confirms that abortion waves on dairy goat farms are the. These are thought to be the earliest known items concerning the pos sible role of monkeys in yellow fever epidemiology, and both episodes origi nated in trinidad. Coordinate surveillance systems to collect, analyse and interpret. Lassa fever is caused by a single stranded rna virus and is a disseminated systemic primary viral infection. The yellow fever virus is a flavivirus with a 400year history. The mean duration of fever before the first medical visit was 11. Yf is a viral sepsis characterised most commonly by a sudden onset of fever and prostration. Lassa fever from the ashanti region of ghana detected in october and december, 2011.
When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Since the steady rise in human cases which started in 2007, q fever has become a major public health problem in the netherlands with 2,357 human cases notified in the year 2009. Epidemiological analyses on african swine fever in the baltic. Pdf epidemiological trends of lassa fever outbreaks and. Of the cases reported so far in the nigerian outbreak, the mortality rate is 43. An epidemiology model suggested by yellow fever john r. Fever tuberculosis viruses zoonoses abstract background.
Mosquitoes capable of transmitting yellow fever exist in regions. The existing outbreak data was not compiled which is important for the provision of epidemiological information as a base for the health care systems, and to make possible preventive and curative measures for the coming dengue fever outbreak. Many of these had not reported dengue for 20 or more years and several have no known history of the disease. Mar 16, 2017 viral hemorrhagic fevers vhfs are a group of febrile illnesses caused by rna viruses from several viral families. Since 2015, major increases in lassa fever attack rate and in the casefatality rate have occurred in this state. Lassa fever annual epidemiological report for 2016 en pdf275. Clinical presentation is varied, mainly presenting with fever, malaise, abdominal discomfort, and nonspecific symptoms often confused with other causes. Lassa fever outbreaks have been confirmed across five west african countries, including nigeria, benin, sierra leone, togo, and burkina faso.
Epidemiology of african swine fever virus sciencedirect. Epidemiological study of relapsing fever in north africa. Lassa fever is an animalborne, or zoonotic, acute viral illness. Nov 21, 20 rift valley fever rvf is an emerging zoonosis posing a public health threat to humans in africa. Keep your home clean and tidy to discourage rats from entering 4. The only south african book dealing with epidemiology as a discipline. In collaboration with the asfaffected member states ms, efsa is updating the epidemiological analysis of asf in the european union which was carried out in 2015. Q fever, or query fever, is a zoonotic disease caused by the bacterium coxiella burnetii. Lassa fever outbreak hits nigeria infectioncontrol. Acronyms 1q 0 infant mortality rate per 1,000 live births 4q 1 child mortality rate between exact age 1 and exact age 5 5q 0 underfive mortality rate per 1,000 live births act artemisinin combination therapy alu artemetherlumefantrine anc antenatal care arv antiretroviral therapy cdc centers for disease control and prevention.
Typhoid fever remains a major health problem worldwide, in contrast to chile, where this disease is an isolated finding. In lassa fever endemic regions such as nigeria, a suspected case is defined 23 as an illness with onset of fever and no response to treatment of usual causes of fever in the ar ea and at. Mission consisting of dr gaud and dr morgan proceeded to french north africa in november 1945 in order to study the epidemic of louseborne relapsing fever which, after 25 years quiescence, had spread rapidly through tunisia, algeria and morocco the last epidemics were in north africa between 1912 and 1915 and in french west africa between 1922 and 1925 during the. Lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by the lassa virus lasv, a member of the family arenaviridae. Baseline mapping of lassa fever virology, epidemiology and. Significant viral hemorrhagic fever and arboviruses 4 10 100. A dengue outbreak in cape verde was recently reported 3,000 cases, and. The causative agent, yellow fever virus yfv, is the prototype of the genus. Many of those infected by the virus do not develop symptoms. Each year more than 33 million people suffer from typhoid globally.
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